Enhanced performance of LED-based photoacoustic imaging using short-lag spatial coherence beamforming: comparative analysis with laser-based imaging

Short-lag spatial coherence beamforming (SLSC) has shown promise in improving the signal-to-noise ratio (SNR) of photoacoustic (PA) images acquired under conditions of low optical fluence. However, the performance of this technique has not yet been evaluated with LED-based PA imaging (PAI). Therefore, the objective of this study was to compare the resulting image quality when applying SLSC and a conventional amplitude-based (FFT) beamformer. The influence of both LED and laser illumination was investigated using the same PAI system on a tissue-mimicking phantom and in ex vivo experiments. In both experimental conditions and illumination strategies, the SLSC method exhibited superior performance compared to FFT. Lowering the LED PAI frame rate, by increasing frame averaging, resulted in more significant SNR improvement for amplitude-based PAI compared to SLSC. For example, in the ex vivo experiment, the SNR values with SLSC exhibited enhancements of 13.6 dB and 11.1 dB for LED and laser illumination at 10 Hz, respectively. Meanwhile, at a frame rate of 0.25 Hz, the improvements were less pronounced, specifically 11.2 dB and 7.4 dB for LED and laser illumination, respectively. In conclusion, our results demonstrate that SLSC can improve SNR of LED-based PAI, particularly in conditions of low-SNR.